Transcript

Long before man came to Iowa the climate in North America was much different than it is today. About a million or so years ago great masses of ice—called glaciers—began forming. Over a period of thousands of years, the glaciers continued to grow until much of North America was covered with ice. So much water was frozen in the glaciers that the oceans of the world became shallower—exposing land which had been under water. One such area of land was exposed between North America and Asia forming a natural bridge between Siberia and Alaska. Along this strip of land, known as the Bering Land Bridge, vegetation grew and the wild animals that fed on the vegetation slowly began to cross this strip of land. Although it took thousands of years, eventually these animal species crossed the land bridge to North America.